diff --git a/src/main/java/org/ntlab/acanthus_server/resources/gallery/InvitesRest.java b/src/main/java/org/ntlab/acanthus_server/resources/gallery/InvitesRest.java
index eb3a411..3f78f1f 100644
--- a/src/main/java/org/ntlab/acanthus_server/resources/gallery/InvitesRest.java
+++ b/src/main/java/org/ntlab/acanthus_server/resources/gallery/InvitesRest.java
@@ -84,7 +84,7 @@
         //既に参加しているかのユーザーのチェック
         for (var editor : animation.getEditors()) {
             if (editor.getUid() == Integer.parseInt(invitedUid)) {
-                var response = Response.status(401).entity("既にユーザーが参加しています.");
+                var response = Response.status(401).entity("既に参加しています.");
                 throw new WebApplicationException(response.build());
             }
         }